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A case study on the efficacy of different roof bolting schemes in Lhoist North America’s Crab Orchard Mine

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International Journal of Mining Science and Technology 2020年第1期30卷 99-104页

作者： Reece Kurre Gabriel Walton Stantec Consulting Services Inc. Walnut CreekCA 94597USA Department of geology and Geological Engineering Colorado School of MinesGoldenCO 80401USA

Roof bolting has long been used in underground mines across the world to provide ground *** roof bolts are cheap and easy to install with the use of specialized machines as a part of the production cycle. Lhoist North America’s Crab Orchard Mine is an underground room and pillar limestone mine that uses mechanically anchored roof bolts for ground support. The mine currently employs two different roof bolting patterns: a standard 1.5 × 1.5 m pattern, and another 0.8 × 0.8 m pattern for use in areas with particularly hazardous roof conditions. The purpose of this study is to evaluate the relative effectiveness of each bolting pattern. A series of numerical models were created using Roc Science’s RS2. The models were based on a symmetrical section of the mine at its deepest point, and were modeled using generalized Hoek-Brown failure criterion along with a discrete fracture network. A series of sensitivity analyses were performed on the models by varying parameters such as joint friction angle, crack persistence, joint randomization, and tensile strength of the limestone. Based on the results of the original models and sensitivity analyses, it appeared that the standard bolting pattern provided sufficient roof support capacity under almost all the expected conditions at the mine, since safety factors below the design value of 1.5 were only found for individual bolts in a few of the worst test cases *** results can help improve the mine’s productivity and reduce operating costs without compromising safety.

关键词： Numerical modeling Mining Roof bolting Roof stability Analysis RocScience’s RS2 Underground stone

2015–2020 Geological Survey Program of China Geological Survey bureau

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Acta Geologica Sinica(English Edition) 2014年第6期88卷 1917-1919页

作者： HAO Ziguo FEI Hongcai LIU Lian HAO Qingqing Susan TURNER Chinese Academy of Geological Sciences Editorial Office of Acta Geologica Sinica (English edition) Geological Society of China Editorial Office of geology and Exploration Institute of Mineral Resources Research China Metallurgical Geology Bureau

On 1–5 September 2014,the China Geological Survey bureau held a 2015–2020 geology and Mineral Resources Investigation and Assessment Special Planning and Deployment Meeting to plan the next six years in order to invest nearly ten billion US dollars to implement 9 programs and 50 projects with the aim of developing geological survey work,and to play a leading role in ensuring sustained and stable development.

关键词： bureau sustained mines programs prospecting geology carrying tectonic geophysics sandstone

Exhalative Lead-Zinc Deposits in Shallow Sea,Southern Xicheng Belt,Gansu Province

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Acta Geologica Sinica(English Edition) 2008年第4期82卷 811-819页

作者： ZHU Xinyou WANG Dongbo WEI Zhiguo QIU Xiaoping WANG Ruiting Beijing Institute of geology and Mineral Resources Beijing 100012 Institute of geology Chinese Academy of Geological Sciences Beijing 100037 No. 106 Team Gansu Geological Bureau of the China National Nuclear Corporation （CNNC）. Lauzhou Gansu 730000 Northwest Geological bureau of the CNNC Xi＇an Shaanxi 710000

SEDEX-type lead-zinc deposits in the southern belt of the Xicheng Devonian basin, Gansu Province has been already identified. However, the sedimentary environment of the limestone and philite of the Xihanshui Group within which the lead-zinc deposits occur is littoral and shallow sea. This is different from those in the northern belt such as the Changba-Lijiagou lead-zinc deposits, which were formed in deep sea. The reef and bioclastic limestone are widespread in the southern belt. Particularly they are associated with lead-zinc ores and there are no striae and banding but massive or disseminated structures. It is discovered that the black chimney consists of sphalerite, ankerite, pyrite and galena, in which black, coarse and radial sphalerite occurs as irregularly veins or cylindricality with a width of 10-40 cm in the center, and it is surround by fine ankerite and minor celestite with ribbon structure. The immediate wall rock of the chimney, reef limestone, was unaltered and the outside reef and bioclastic limestone were intensively silicified. Those silicified reef and bioclastic limestone host disseminated lead-zinc ores of the Luoba and Bijiashan type. It is concluded that the exhalative system occurred in a shallow sea in the Givetian of the middle Devonian. Brine is boiled due to low pressure, and a great deal of lead and zinc was dispersed in the interface between the limestone and phyllite and formed a source bed. In the Triassic period, meta-hydrothermal fluids leached and extracted metals from the source bed, and then moved and mineralized in open space such as arches and inverse limbs of anticlines, and formed massive and vein ores such as the Jianyagou and Dengjiashan type deposits.

关键词： sedimentation-exhalation type ore-forming model shallow sea Qinling Gansu Shaanxi

Petrogenesis of Two Types of Archean TTGs in the North China Craton:A Case Study of Intercalated TTGs in Lushan and Non-intercalated TTGs in Hengshan

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Acta Geologica Sinica(English Edition) 2016年第6期90卷 2049-2065页

作者： SHAN Houxiang ZHAI Mingguo DEY Sukanta State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Department of Applied geology Indian School of MinesDhanbad 826004India

TTG （Tonalite-Trondhjemite-Granodiorite） gneisses, a major component of Precambrian continental crust, play a significant role in understanding the process and mechanism of the crustal evolution in the early periods of the Earth. In terms of field occurrence, there are two kinds of Archean TTGs in the NCC （North China Craton）： intercalated and non-intercalated TTGs. In this contribution, we make a comprehensive comparison of these two types of TTGs from the typical areas （Lushan and Hengshan） in the NCC with an aim to constrain their petrogenesis. The results suggest that they have similar mineral assemblages of Pl ＋ Qtz ＋ Bt ± Amp ± Kfs but different field appearances and geochemical compositions, thus probably reflecting different source materials and tectonic settings. Differences in the contents of characteristic elements, such as Sr, REE and HFSE, suggest that the non-intercalated TTGs in Hengshan were generated at deeper levels than those of intercalated TTGs in Lushan. Constraints from element contents and geochemical modeling results are consistent with derivation from dual sources involving both garnet amphibolite and rutile-bearing eclogite residues for the non-intercalated TTGs in Hengshan, whereas the compositions of intercalated TTGs in Lushan indicate that they were formed by partial melting with amphibolite to garnet-amphibolite residues. Moreover, accumulation of plagioclase is also required in the petrogenesis of intercalated TTGs in Lushan, at least for part of them. In addition, the non-intercalated TTGs in Hengshan display distinctly higher MgO, Mg#, Cr and Ni values and lower SiO2 average contents compared to the intercalated TTGs in Lushan. These features suggest that the former magma, at least a part, might have interacted with the mantle wedge during ascent. Considering all the above factors and in combination with the whole-rock Nd and zircon Hf isotopic data, it is suggested that the non-intercalated TTGs in Hengshan were produced by partia

关键词： TTGs petrogenesis crustal growth Archean North China Craton

Geochemical signatures of potassium metasomatism in anthracite from the Himalayan fold‑thrust belts of Sikkim,India

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International Journal of Coal Science & Technology 2022年第2期9卷 48-69页

作者： Santanu Ghosh Anwita Ojha Atul Kumar Varma Coal geology and Organic Petrology Laboratory Department of Applied GeologyIndian Institute of Technology(Indian School of Mines)DhanbadJharkhand 826004India Department of Earth Sciences Indian Institute of Technology BombayPowaiMumbaiMaharashtra 400076India

The present study focuses on the inorganic geochemical features of the bituminous coal samples from the Raniganj and the Jharia Basins,as well as the anthracite samples from the Himalayan fold-thrust belts of Sikkim,*** SiO_(2)content(48.05 wt%to 65.09 wt%and 35.92 wt%to 50.11 wt%in the bituminous and anthracite samples,respectively)and the ratio of Al_(2)O_(3)/TiO_(2)(6.97 to 17.03 in the bituminous coal samples and 10.34 to 20.07 in the anthracite samples)reveal the intermediate igneous source rock composition of the *** ratio of the K_(2)O/Al_(2)O_(3)in the ash yield of the bituminous coal samples(0.03 to 0.09)may suggest the presence of kaolinite mixed with montmorillonite,while its range in the ash yield of the anthracite samples(0.16 to 0.27)may imply the presence of illite mixed with *** chemical index of alteration values may suggest the moderate to strong chemical weathering of the source rock under sub-humid to humid climatic *** plot of the bituminous coal samples in the A–CN–K diagram depicts the traditional weathering trend of parent rocks,but the anthracite samples plot near the illite feld and are a bit ofset from the weathering *** may imply the plausible infuences of the potassium-metasomatism at post coalifcation stages,which is further supported by high K_(2)O/Na_(2)O ratio(29.88–80.13).The Fourier transform infrared spectra further reveal the hydroxyl stretching intensity of illite in the anthracite samples substantiating the efect of the epigenetic *** decrease in total kaolinite intensity/compound intensity of quartz and feldspar may provide additional evidence towards this epigenetic event.

关键词： Himalayan fold-thrust belts Anthracite Potassium metasomatism Kaolinite to quartz-feldspar intensity ratio Montmorillonite stretching and bending intensities Illite-stretching frequency

Improved estimation of PM_(2.5) brown carbon contributions to filter light attenuation

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Particuology 2021年第3期19卷 1-9页

作者： Judith C.Chow L.-W.Antony Chen Xiaoliang Wang Mark C.Green John G.Watson Division of Atmospheric Sciences Desert Research InstituteRenoNVUSA State Key Laboratory of Loess and Quaternary geology Institute of Earth EnvironmentChinese Academy of SciencesXi’anChina Graduate Faculty Department of Atmospheric SciencesUniversity of NevadaReno NevadaUSA Department of Environmental and Occupational Health School of Public HealthUniversity of NevadaLas VegasNVUSA

Multiwavelength light attenuation measurements have been acquired as part of thermal/optical carbon analysis in the *** Speciation Network(CSN)and the Interagency Monitoring of PROtected Visual Environments(IMPROVE)network beginning in *** are used to estimate PM_(2.5)brown carbon(BrC)contributions to light absorption at various wavelengths,a useful method for separating biomass burning contributions from other *** of light transmitted through the filter deviates from Beers Law as the mass of light absorbing materials *** study estimates the effects of these deviations with empirical adjustment factors applied to samples for CSN from 2016 to 2017 and for IMPROVE from 2016 to *** for the filter loading effect results in an annual average increase of∼6-7%BrC contribution to light attenuation:from 3.6%to 10.7%for the urban,more heavily loaded CSN samples;and from 23.7%to 29.5%for the non-urban IMPROVE *** alternative method is examined for BrC and black carbon(BC)adjustments by calculating the AbsorptionÅngström Exponent(AAE)for BC(i.e.,AAE_(BC))based on the ratios of 635 nm/780 nm light attenuation rather than assuming AAE_(BC)of *** paired-wavelength calculations result in a median AAE_(BC)of 0.76 for CSN and 0.8 for IMPROVE,with the majority of samples(i.e.,91%of CSN and 70%of IMPROVE)showing AAE_(BC)<*** assuming negligible contributions from BrC to AAE at longer wavelengths,the amount of light attenuation at shorter wavelengths(e.g.,405 nm)where BrC is dominant can be *** paired-wavelength method applied to the filter loading adjusted data has a greater effect on urban(fresh)than on non-urban(aged)aerosols,resulting in a factor of two increase in annual averaged BrC light attenuation(from 10.7%to 21.6%)for CSN and by a factor of 1.11(from 29.5%to 32.7%)for IMPROVE *** result demonstrates the importance of particle loading and AAE correction on quantifying BrC light attenuatio

关键词： Organic carbon Brown carbon Elemental carbon Black carbon AbsorptionÅngström Exponent

Tracking the Tectonic Evolution of the Junggar-Balkhash Ocean: A Case Study from the Post-Collisional Takergan Pluton in the West Junggar, Xinjiang

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Journal of Earth Science 2021年第5期32卷 1250-1261页

作者： Yangbaihe Hong Bo Liu Key Laboratory of Ministry of Education on Safe Mining of Deep Metal mines Department of GeologySchool of Resources and Civil EngineeringNortheastern UniversityShenyang 110819China

The Late Carboniferous and Early Permian igneous rocks are widely developed in the West Junggar, Xinjiang, which are considered to be related to the evolution of the Junggar-Balkhash Ocean. However, their tectonic settings have been controversial for a long time. With the aim of providing new evidence for the Late Paleozoic tectonic evolution of the West Junggar, we present petrology, zircon U-Pb chronology, whole-rock major and trace elemental and Sr-Nd isotopic data, to discuss the petrogenesis and tectonic setting of Takergan pluton from the Barleik Mountains in the West Junggar. The Takergan pluton is mainly composed of quartz diorite porphyry and quartz monzonite. The quartz diorite porphyry has low Si O2(57.76 wt.%–57.81 wt.%), high total alkali contents(Na2 O+K2 O=6.29 wt.%–6.56 wt.%), and high Mg# values(45–46), with a zircon U-Pb age of 304±5 Ma. The quartz monzonite shows relatively high SiO2(58.71 wt.%–64.71 wt.%), total alkali contents(7.73 wt.%–9.70 wt.%), and Mg^(#) values(34–47), with the A/CNK values of 0.91–0.98, which belongs to shoshonitic and metaluminous I-type granite series. The quartz monzonite yields zircon U-Pb ages of 302±2 and 296±3 Ma, and is characterized by low initial Sr ratios of 0.703 97–0.704 09, high εNd(t) values of +6.8– +7.0, and young Nd model ages of 551–587 Ma. Both the quartz diorite porphyry and quartz monzonite are enriched in light rare earth elements and Rb, Th, U, K, and depleted in Nb, Ta, Ti, with different degrees of negative Eu anomalies. These features indicate that the Takergan pluton was most likely formed in a post-collisional setting by partial melting of a depleted mantle source that had been metasomatized by subduction-related fluids, with significant fractional crystallization and slightly contaminated by crustal materials. Combined with the widespread distribution of the coeval stitching plutons, the occurrences of terrestrial Late Carboniferous to Permian volcano-sedimentary formations, and the absence of

关键词： Junggar-Balkhash Ocean post-collisional magmatism central Asian orogenic belt West Junggar

Fluid Inclusion Studies of the Skarn-type Tin Mineralization at Red-A-ven,Northwest Dartmoor,England

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Chinese Journal Of Geochemistry 1992年第4期11卷 362-369页

作者：彭齐鸣 A.V.BROMLEY Department of geology Changchun College of GeologyChangchun130061 Camborne School of mines PoolRedruthCornwallRT15 3SEUK

Two principal hydrothermal events have been recognized ,which resulted in the tin-bearing skarns at Red-A-ven ,Northwest *** was enriched during both the early (occurring as tin-bearing andradite) and late hydrothermal events (mainly as malayaite stannite and cassiterite,accompanied by boron silicates and minor tungsten).Thermometric measurements of fluid inclusions in diopside,garnet,malayaite,tourmaline-quartz and axinite were carried out,suggesting that the early skarns were formed at the temperature above 600℃and the salinities ranging from 10 to 20 wt.% NaCl *** the late skarns at the temperatures of 350-460℃ and the salinities ranging from 30 to 50wt.% NaCl *** estimated minimum depths are 2856m(850 bar) for the early event and 2526m(185 bar) for the late *** birefringence of the andradite might be related with the superimposition of late hydrothermal fluids.

关键词：流体包裹体锡矿床硅卡岩成矿作用英国达特姆尔高原

Strategies towards statistically robust interpretations of in situ U-Pb zircon geochronology

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Geoscience Frontiers 2016年第4期7卷 581-589页

作者： Christopher J.Spencer Christopher L.Kirkland Richard J.M.Taylor The Institute of Geoscience Research(TIGeR) Department of Applied GeologyWestern Australian School of MinesCurtin UniversityWA 6102Australia Centre for Exploration Targeting-Curtin Node Department of Applied GeologyWestern Australian School of MinesCurtin UniversityWA 6102Australia Australian Research Council Centre of Excellence for Core to Crust Fluid SystemsPerthWA 6102Australia

Zircon U-Pb geochronology has become a keystone tool across Earth science, arguably providing the gold standard in resolving deep geological time. The development of rapid in situ analysis of zircon （via laser ablation and secondary ionization mass spectrometry） has allowed for large amounts of data to be generated in a relatively short amount of time and such large volume datasets offer the ability to address a range of geological questions that would otherwise remain intractable （e.g. detrital zircons as a sedi- ment fingerprinting method）. The ease of acquisition, while bringing benefit to the Earth science com- munity, has also led to diverse interpretations of geochronological data. In this work we seek to refocus U -Pb zircon geochronology toward best practice by providing a robust statistically coherent workflow. We discuss a range of data filtering approaches and their inherent limitations （e.g. discordance and the reduced chi-squared; MSWD）. We evaluate appropriate mechanisms to calculate the most geologically appropriate age from both 238U/206pb and 207pb/206pb ratios and demonstrate the cross over position when chronometric power swaps between these ratios. As our in situ analytical techniques become progressively more precise, appropriate statistical handing of U-Pb datasets will become increasingly pertinent.

关键词： Zircon Geochronology U-Pb Geostatistics MSWD